Simultaneous high‐performance liquid chromatography with tandem mass spectrometry quantification of six bioactive components in rat plasma after oral administration of Yougui pill

Yougui pills are a classic Chinese medicine that shows significant effects on nerve regeneration and neuroprotection in modern pharmacological studies. With a complex formula, Yougui pills have faced significant challenges in the fields of bioanalysis and pharmacokinetics in animals and human studies. In the present study, a specific and accurate high‐performance liquid chromatography with tandem mass spectrometry method was developed and validated for the quantitative determination of the six bioactive components in rat plasma after oral administration of Yougui pills. Chromatographic separation was performed on a C18 column with a gradient elution system. Samples were analysed using positive ion mode with multiple reaction monitoring mode. The assay showed good linearity for all six bioactive components in the dynamic range of 0.50 to 50 ng/mL with acceptable intra‐ and inter‐batch accuracy and precision. The lower limits of quantification were 0.50 ng/mL for all six bioactive components. The method was successfully applied to rat pharmacokinetics after oral administration of Yougui pills. All six bioactive components were detected in rat plasma, including songorine, benzoylhypaconitine, benzoylmesaconitine, neoline, karacoline, and sweroside, while some other target compounds were not detected, such as rhmannioside A, loganin, and cornuside I. After oral administration of Yougui pills at a dose of 2500 mg/kg, all six bioactive components were rapidly absorbed, resulting in t_max values less than 1 h and relative lower C_max values. The t_1/2 values for songorine, benzoylhypaconitine, benzoylmesaconitine, neoline, karacoline, and sweroside were calculated to be 2.62 ± 0.67, 2.11 ± 0.45, 1.94 ± 0.35, 1.88 ± 0.31, 2.07 ± 0.44, and 1.59 ± 0.30 h, which indicated that Yougui pills should be taken in multiple oral doses over a relatively short period.     

A LC‐MS/MS method for simultaneous determination of seven alkaloids in rat plasma after oral administration of Phellodendri chinensis cortex extract and its application to a pharmacokinetic study

A sensitive and rapid liquid chromatography with tandem mass spectrometry method has been developed for simultaneous determination of berberine (I), jateorhizine (II), palmatine (III), tetrahydropalmatine (IV), phellodendrine (V), protopine (VI) and columbamine (VII) in rat plasma after oral administration of Phellodendri chinensis cortex extraction. The plasmas were extracted by liquid‐liquid extraction. The tandem mass spectrometric detection was performed in the multiple reaction monitoring mode in the positive ionization. The intra‐ and interday precisions and accuracies were in range from ?12.18 to 13.21%. Mean absolute recoveries of all analytes and internal standard were between 78.6 and 98.9%. The seven alkaloids were proven to be stable during sample storage and analysis procedures. The established method was validated and successfully applied to pharmacokinetics study in rat plasma after oral administration of Phellodendri chinensis cortex extract. The t_1/2 of palmatine, columbamine, pellodendrine, berberine, tetrahydropalmaine, jatrorrhizine, and protopine were 5.16, 5.96, 7.18, 19.84, 6.28, 7.08, 6.90 h, respectively. The seven compounds could be rapidly absorbed into blood (time for maximal concentration, 1.80–1.93 h). This study could establish a foundation for further research of Phellodendri chinensis cortex and might provide more useful information to guide the clinical usage.     

Development and validation of a UHPLC–MS/MS method for the simultaneous determination of five bioactive flavonoids in rat plasma and comparative pharmacokinetic study after oral administration of Xiaochaihu Tang and three compatibilities

An accurate, rapid, and reliable ultra high performance liquid chromatography with tandem mass spectrometry method was developed and validated for the simultaneous determination of baicalin, wogonoside, baicalein, wogonin, and oroxylin A in rat plasma. Then, the stability of baicalin and baicalein in the preparation of plasma sample was systematically investigated. The Waters BEH C₁₈ column was used with a gradient mobile phase system of acetonitrile and water containing 0.1% formic acid. The analytes were detected in the multiple reaction monitoring mode with positive electrospray ionization. 100 μL fresh plasma was added with 50 μL antioxidant reagent (1 mol/L HCl containing 0.5% Vitamin C), and liquid–liquid extraction with ethyl acetate was used to extract the analytes from plasma. Lower limits of quantification of baicalin, wogonoside, baicalein, wogonin, and oroxylin A were 21.9, 4.80, 1.20, 0.848, and 0.800 ng/mL, respectively. The mean extract recoveries of five flavonoids were 69.1∼89.2%, and the precision and accuracy were within the acceptable limits. This method was further successfully applied to the comparative pharmacokinetic study of these five flavonoids in rats after oral administration of Xiaochaihutang and three compatibilities. The obtained results may be helpful to reveal the mechanism of Xiaochaihutang formula compatibility.     

A simple liquid chromatography coupled with tandem mass spectrometry approach for the simultaneous quantification of thirteen compounds in rats following oral administration of raw and processed Fructus Xanthii: Application in a comparative pharmacokinetic study

A simple and sensitive analysis using ultra high performance liquid chromatography with a tandem mass spectrometric system operated in selected reaction monitoring mode was developed for the determination of 11 phenolic acids, atractyloside, and carboxyatractyloside in rat plasma. The two classes of analytes were then separated on a Waters ACQUITY? UPLC HSS T3 column (50 mm × 2.1 mm, 1.8 µm) using gradient elution with a mobile phase of 0.2% formic acid in water containing 10 mM ammonium acetate and methanol. Detection was accomplished by selected reaction monitoring scanning via an electrospray source operating in negative ionization mode. The calibration curve was linear (R² = 0.990) over a concentration range of 1.20–3500 ng/mL, while the validated lower limit of quantification was 1.20 ng/mL. The precision varied from 0.84 to 4.62%, and the accuracy varied within ±5%. The method proved robust with sample freezing and thawing and with short‐ and long‐term sample storage. The established method was used for simultaneous quantification and was successfully used for the first time for the pharmacokinetic evaluation of 13 compounds after the intragastric administration of raw and processed Fructus Xanthii in rats. The results indicated that processing affects the absorption and metabolism of Fructus Xanthii extract. Importantly, the results also indicated the importance of processing for the clinical application of traditional Chinese medicine.     

Simultaneous determination of multiple active components in rat plasma using ultra‐fast liquid chromatography with tandem mass spectrometry and application to a comparative pharmacokinetic study after oral administration of Suan‐Zao‐Ren decoction and Suan‐Zao‐Ren granule

Suan‐Zao‐Ren decoction has been used to treat insomnia for many years. In this work, a rapid and sensitive ultra‐fast liquid chromatography with tandem mass spectrometry method was first developed and fully validated for the simultaneous quantification of seven main active components, spinosin, mangiferin, neomangiferin, ferulic acid, liquiritin, isoliquiritin, and liquiritin apioside in rat plasma. The method was also successfully applied to compare the pharmacokinetics of these active ingredients after oral administration of Suan‐Zao‐Ren decoction and Suan‐Zao‐Ren granule. The separation was achieved on a Venusil MP C₁₈ column and the detection was conducted by the multiple reaction monitoring mode using negative ion mode. Each calibration curve had good linearity over a wide concentration range. The precision of intra‐ and interday were all within 15%, and the extraction recoveries at different analyte concentrations were all above 82.0%. The established method was successfully applied to compare the pharmacokinetic profiles of the analytes between Suan‐Zao‐Ren decoction and Suan‐Zao‐Ren granule groups. The results indicated that all the analytes had similar mean concentration‐time curves trend between two groups. No significant differences were observed in pharmacokinetic parameters of mangiferin, while the others had significant differences.     

Ultra‐fast liquid chromatography with tandem mass spectrometry determination of eight bioactive components of Kai‐Xin‐San in rat plasma and its application to a comparative pharmacokinetic study in normal and Alzheimer's disease rats

A method of ultra‐fast liquid chromatography with tandem mass spectrometry was developed and validated for the simultaneous quantitation of eight bioactive components, including polygalaxanthone III, sibiricaxanthone B, tenuifolin, sibiricose A5, sibiricose A6, tenuifoliside A, ginsenoside Re and ginsenoside Rb1 in rat plasma after oral administration of Kai‐Xin‐San. The plasma samples were extracted by liquid–liquid extraction using digoxin as an internal standard. Chromatographic separation was performed on a Venusil MP C₁₈ column (100 mm × 2.1 mm, 3 μm) with methanol and 0.05% acetic acid in water as mobile phase. The tandem mass spectrometric detection was performed in the multiple reaction monitoring with turbo ion spray source in the negative ionization. Validation parameters were within acceptable ranges. The established method has been successfully applied to compare the pharmacokinetic profiles of the analytes between normal and Alzheimer's disease rats. The results indicated that there were significant differences in pharmacokinetic parameters of some components between two groups, which may be due to the mechanisms of Alzheimer's disease and pharmacological effects of the analytes. The pharmacokinetic research in the pathological state might provide more useful information to guide the clinical usage of herbal medicine.     

An ultra high performance liquid chromatography with tandem mass spectrometry method for simultaneous determination of thirteen components extracted from Radix Puerariae in rat plasma and tissues: Application to pharmacokinetic and tissue distribution study

A rapid and sensitive ultra high performance liquid chromatography with tandem mass spectrometry method was established and validated for simultaneous determination of thirteen bioactive components (gallic acid, protocatechuic acid, puerarin, p‐hydroxycinnamic acid, daidzin, ononin, daidzein, naringenin, genistein, apigenin, formononetin, biochanin A, and β‐sitosterol) of Radix Puerariae extract in rat plasma and tissues. The plasma and tissues samples were pretreated by protein precipitation extraction, and umbelliferone and rutin were used as internal standards. Sample separation was performed on a ZORBAX RRHD Eclipse plus C₁₈ column (2.1 mm × 50 mm, 1.8 µm, Agilent) with a mobile phase consisting of methanol–water (containing 0.1% formic acid). The mass spectrometry analysis was conducted in positive and negative ionization modes with multiple reaction monitoring. The lower limit of quantitation range for the 13 analytes was 0.2?35 ng/mL. The intra‐ and inter‐day precision of all the analytes were less than 10.92%, with an accuracy ranging from ?13.10 to 11.96%. Both the recovery and matrix effect were within acceptable limits. This method was successfully applied to pharmacokinetic and tissue distribution study of the 13 bioactive components in rats after oral administration of R. Puerariae extract.     

Simultaneous determination of ferulic acid and gastrodin of Tianshu Capsule in rat plasma by ultra‐fast liquid chromatography with tandem mass spectrometry and its application to a comparative pharmacokinetic study in normal and migraine rats

Tianshu Capsule, consisting of Ligusticum chuanxiong Hort and Gastrodia elata Blume, is a widely used Traditional Chinese Medicine preparation for the treatment of migraine. Ferulic acid and gastrodin are main active constituents in Ligusticum chuanxiong Hort and Gastrodia elata Blume, and have been used as marker components for quality control of Tianshu Capsule. In this study, a selective, sensitive, and reliable ultra‐fast liquid chromatography with tandem mass spectrometry method was developed for simultaneous determination of ferulic acid and gastrodin in rat plasma using geniposide as internal standard. The plasma samples were extracted by protein precipitation with methanol after acidification and separated on a Shim‐Pack XR‐ODS C₁₈ column (75 × 3.0 mm, 2.2 μm) using gradient elution with a mobile phase consisting of water (containing 0.1% formic acid) and acetonitrile at a flow rate of 0.6 mL/min. Detection was performed on 3200 QTRAP mass spectrometry equipped with turbo ion spray source in negative ionization mode. Validation parameters were within acceptable ranges. The validated method was applied to compare the pharmacokinetic profiles of ferulic acid and gastrodin in normal and migraine rats. Our results showed that there were remarkable differences in the pharmacokinetic properties of the analytes between the normal and migraine groups.     

Simultaneous determination and pharmacokinetics study of four quinones in rat plasma by ultra high performance liquid chromatography with electrospray ionization tandem mass spectrometry after the oral administration of Qianzhi capsules

A sensitive, specific, and accurate ultra high‐performance liquid chromatography with electrospray ionization tandem mass spectrometry method was developed and validated for the simultaneous quantification of purpurin, munjistin, mollugin, and alizarin from Qianzhi capsules in rat plasma. Chromatographic separation was performed on an Agilent Eclipse Plus C₁₈ RRHD column with a mobile phase consisting of methanol and 5 mM ammonium acetate/water with gradient elution. The analytes were quantified on a triple quadrupole mass spectrometer, operating in the multiple reaction monitoring mode and switching the electrospray ion source polarity with positive electrospray ionization in a single run. Samples were pretreated by liquid–liquid extraction with cyclohexane. The intra‐ and interday precision and accuracy of the assay were within acceptable ranges. Matrix effects for all of the analytes were between 90.16 and 100.21%. The average recovery ranged from 75.38 to 88.96%. This method was successfully applied to study the pharmacokinetic parameters of the four compounds in rat plasma after oral administration of Qianzhi capsules. Four quinones could be rapidly absorbed into blood (t_max, 0.80–1.93 h) and eliminated relatively slowly (t_1/2, 8.07–11.97 h). The results might be helpful for guiding the clinical application of Qianzhi capsules in the future.     

Liquid chromatography-mass spectrometry method for the determination of venlafaxine in human plasma and application to a pharmacokinetic study

A sensitive and selective liquid chromatographic-mass spectrometric (LC-MS) method for the determination of venlafaxine in human plasma has been developed. Samples were prepared using liquid-liquid extraction and analyzed on a C(18) column interfaced with a triple quadrupole mass spectrometer. Positive electrospray ionization was employed as the ionization source. The mobile phase was methanol-water containing 10 mmol/L ammonium acetate, pH 7.9 adjusted with aqueous ammonia (80:20, v/v) at the flow rate of 1.0 mL/min. The analyte and internal standard clozapine were both detected by use of selected ion monitoring mode. The method was linear in the concentration range of 1.0-200.0 ng/mL. The lower limit of quantification (LLOQ) was 1.0 ng/mL. The intra- and inter-day relative standard deviation across three validation runs over the entire concentration range was less than 10.1%. The accuracy determined at three concentrations (5.0, 50.0 and 150.0 ng/mL for venlafaxine) was within +/-10.0% in terms of relative error (RE). The method was successfully applied for the evaluation of pharmacokinetic profiles of venlafaxine capsule in 20 healthy volunteers. The results show AUC, T(max), C(max) and T(1/2) between the testing formulation and reference formulation have no significant difference (p > 0.05). Relative bioavailability was 103.4 +/- 14.1%.     

Nine components pharmacokinetic study of rat plasma after oral administration raw and prepared Semen Cassiae in normal and acute liver injury rats

In China, Semen Cassiae has long been used to protect liver, brighten eyes, and relieve constipation. Prepared Semen Cassiae is produced from raw Semen Cassiae by processing, the two forms of Semen Cassiae have different clinical applications. Pathological state is an important factor affecting the efficacy of drugs, the pharmacokinetic behavior of drugs could be significantly changed when people or animal were under different pathological state. To clarify the effect of processing mechanism and pathological state for pharmacokinetic behavior, the pharmacokinetics of nine components of raw and prepared Semen Cassiae under normal and acute liver injury rats were examined. The results showed that the bimodal phenomenon appeared on the plasma concentration‐time profiles of obtusin, emodin, chrysophanol, aloe emodin and rhein. The T_max of aurantio‐obtusin, obtusin, chrysoobtusin, emodin, chrysophanol, aloe emodin, physcion in normal groups administrated prepared Semen Cassiae were shorter than those administrated raw Semen Cassiae. For the AUC_0–t, aurantio‐obtusin, obtusin, chrysoobtusin, chrysophanol, aloe emodin and physcione in model groups administrated prepared Semen Cassiae were significantly higher than other groups, unlike above components, rhein had poor absorption in model groups. The study would be useful for further studies on pharmacokinetics and clinical application of raw and prepared Semen Cassiae.     

Simultaneous detection of four flavonoids and two alkaloids in rat plasma by LC–MS/MS and its application to a comparative study of the pharmacokinetics between Abri Herba and Abri mollis Herba extract after oral administration

Abri Herba and Abri mollis Herba both were important members of the Leguminosae family in southwestern China. Abri mollis Herba was often used as Abri Herba due to their proximity, but there are few studies on pharmacokinetics to compare their main identical active compositions. A sensitive and selective high‐performance liquid chromatography with tandem mass spectrometry method in the positive/negative electrospray ionization switching mode was developed and validated for the simultaneous analysis of four flavonoids and two alkaloids in rat plasma. The chromatographic separation was carried out on a C18 column with a gradient mobile phase consisting of methanol and 0.5% acetic acid. The detection of the target compounds was conducted in multiple‐reaction monitoring mode with a hybrid triple quadrupole linear ion trap mass spectrometer equipped with positive/negative ion‐switching electrospray ion source. The differences in pharmacokinetics were discovered, which indicated that the substitution between them is some degree of irrationality. The validated method was successfully applied to pharmacokinetic study of the six components in male rat plasma after oral administration of Abri Herba and Abri mollis Herba extract and the results in the study would provide a useful guide for the clinical application of Abri Herba with those in Abri mollis Herba.     

Simultaneous determination of atractylenolide II and atractylenolide III by liquid chromatography-tandem mass spectrometry in rat plasma and its application in a pharmacokinetic study after oral administration of Atractylodes Macrocephala Rhizoma extract

Atractylenolide II (AII) and atractylenolide III (AIII) are the major active components in Atractylodes Macrocephala Rhizoma (AMR). In this study, a sensitive, rapid and selective liquid chromatography–tandem mass spectrometry (LC‐MS/MS) method was developed and validated for the simultaneous determination of AII and AIII in rat plasma using loliolide as internal standard (IS). After protein precipitation with ethyl acetate, the analytes were injected into an LC‐MS/MS system for quantification. Chromatography was performed using a C₁₈ column, eluting with water and acetonitrile (45:55, v/v) at 0.2 mL/min. All analytes including IS were monitored under positive ionization conditions by multiple reaction monitoring with an electrospray ionization source. The validated method was successfully applied to the pharmacokinetic study of AII and AIII in rat plasma after oral administration of AMR extract. The results provided a meaningful basis for evaluating the clinical applications of traditional Chinese medicine. Copyright © 2012 John Wiley & Sons, Ltd.     

Simultaneous determination of eight bioactive constituents of Zhi‐Zi‐Hou‐Po decoction in rat plasma by ultra high performance liquid chromatography with tandem mass spectrometry and its application to a pharmacokinetic study

Zhi‐Zi‐Hou‐Po Decoction, consisting of Gardenia jasminoides Ellis, Magnolia officinalis Rehd. et Wils., and Citrus aurantium L, is a classical Traditional Chinese Medicine formula for the treatment of depression. In order to make good and rational use of this formula in the future, a sensitive, selective, and reliable ultra high performance liquid chromatography with tandem mass spectrometry method was developed for simultaneous determination of two iridoid glycosides (geniposide and genipin gentiobioside), two lignans (honokiol and magnolol), four flavonoid glycosides (isonaringin, naringin, hesperidin, and neohesperidin), the major bioactive constituents of Zhi‐Zi‐Hou‐Po Decoction, in rat plasma using paeoniflorin as internal standard. Plasma samples were pretreated by a simple protein precipitation with acetonitrile. Chromatographic separation was performed on a shim‐pack XR‐ODS C₁₈ column (75 × 3.0 mm, 2.2 µm) using gradient elution with mobile phase consisting of 0.1% formic acid aqueous solution and acetonitrile at a flow rate of 0.5 mL/min. Mass spectrometric detection was conducted on a 3200 QTRAP mass spectrometry equipped with electrospray ionization source in negative ionization mode. Quantification was performed using multiple reactions monitoring mode. Calibration curves exhibited good linearity (r > 0.9947) over a wide concentration range for all analytes, and the lower limits of quantification were 10, 5, 1, 5, 1, 5, 1, and 5 ng/mL for geniposide, genipin gentiobioside, honokiol, magnolol, isonaringin, naringin, hesperidin, and neohesperidin, respectively. The intraday and interday precisions at three quality control levels were less than 12.3% and the accuracies ranged from ?11.2 to 10.7%. Extraction recovery, matrix effect, and stability were satisfactory in rat plasma. The validated method was successfully applied to a pharmacokinetic study of the eight analytes after oral administration of Zhi‐Zi‐Hou‐Po decoction to rats.     

Development of a liquid chromatography–tandem mass spectrometry method for simultaneous determination of five isoflavonoids and seven neurochemicals in rat brain dialysate and its application to a pharmacological study

Pueraria lobata is a medicinal plant widely used in traditional Chinese medicine. The total pueraria isoflavones have demonstrated positive effect against neurological disorders. In the present study, we first develop an ultra high performance liquid chromatography and tandem mass spectrometry method to quantify the multiple active pueraria isoflavonoids and neurochemical markers in brain dialysate to provide tools for further exploring the functional mechanism of pueraria isoflavones for neuroactivities. A phenomenex Luna C18 column (50 × 2.0 mm, 5 μm) was employed with acetonitrile/0.05% formic acid in water as the mobile phase for the separation of analytes. A mass spectrometer with electrospray ionization source in positive/negative ion switching mode was used for multiple reaction monitoring of the detected compounds. The method was validated and proved acceptable. The intra‐ and interday precision across quality control levels was within 13.87 for all analytes, whereas the deviation of assay accuracies ranged between 0.03 and 11.53%. The method was successfully applied to a pharmacological study of pueraria isoflavones in rat brain.     

UHPLC–MS/MS method for the simultaneous quantitation of five anthraquinones and gallic acid in rat plasma after oral administration of prepared rhubarb decoction and its application to a pharmacokinetic study in normal and acute blood stasis rats

Prepared rhubarb, as one of the main processed products of rhubarb, has a good effect on promoting blood circulation. In this paper we describe a rapid, sensitive, and selective ultra‐fast liquid chromatography with tandem mass spectrometry method for simultaneous quantification of five anthraquinones (rhein, aloe‐emodin, chrysophanol, emodin, and physcion) and gallic acid in plasma. Chromatographic separation was performed on an Extend C₁₈ column at the temperature of 30°C using a mobile phase that consisted of 0.1% aqueous formic acid and acetonitrile. Satisfactory linearity, precision, accuracy, extraction recovery, and matrix effect have been achieved. Then, the validated method was successfully applied to a comparative pharmacokinetic study. The results might be helpful for guiding clinical application of prepared rhubarb in the future.     

Comparative pharmacokinetic study of pyranocoumarins and khellactone in normal and acute lung injury rats after oral administration of Peucedanum praeruptorum Dunn extracts using a rapid and sensitive liquid chromatography–tandem mass spectrometry method

Pyranocoumarins are the main constitutes in Peucedanum praeruptorum Dunn and possess various biological activities. In this article, we developed and validated a rapid and sensitive liquid chromatography–tandem mass spectrometry method for the targeted quantification of the pyranocoumarins, praeruptorin A, praeruptorin B and praeruptorin E, and khellactone, which is a common metabolite of these pyranocoumarins in rat plasma samples. We then performed a comparative pharmacokinetic study of these pyranocoumarins and khellactone in normal and lipopolysaccharide‐induced acute lung injury (ALI) in rats following oral administration of P. praeruptorum Dunn extracts. Calibration curves gave desirable linearity (r > 0.99) and the lower limit of quantifications were sufficient for quantitative analysis. The precision and accuracy were assessed by intra‐batch and inter‐batch assays, and the relative standard deviations were all within 10.23% and the accuracy (relative error) was between −5.52% and 8.68%. The extraction recoveries, matrix effects and stability were also acceptable. The pharmacokinetic study revealed that the area under the concentration–time curve (0–t ) of khellactone in ALI rats was significantly decreased compared with the normal rats. Meanwhile, the systemic exposures of these pyranocoumarins were slightly higher in the ALI rats than those in normal rats were. The pharmacokinetic study in the pathological state might provide information that was more comprehensive to guide the clinical usage of P. praeruptorum Dunn.      

Simultaneous determination of five triterpene acids in rat plasma by liquid chromatography–mass spectrometry and its application in pharmacokinetic study after oral administration of Folium Eriobotryae effective fraction

Folium Eriobotryae effective fraction (FEA), the extract of Folium Eriobotryae, had been used as anti‐hyperglycemia and anti‐hyperlipemia medicine in China. A previous study indicated that euscaphic acid, maslinic acid, corosolic acid, oleanolic acid and ursolic acid, the five structurally similar triterpene acids (containing two groups of structural isomers), are the major components of FEA. In the present study, we developed a specific and reliable LC‐MS method for simultaneous determination of the five triterpene acids in rat plasma, and further investigated their pharmacokinetic properties after oral administration of FEA. Following a simple sample preparation, chromatographic separation was achieved on a C₁₈ column with a mobile phase composed of methanol–0.1% ammonium acetate (80:20, v/v). Quantification was achieved by monitoring the selected ions at m/z 487.6 for euscaphic acid, m/z 471.5 for maslinic acid and corosolic acid, m/z 455.5 for oleanolic acid and ursolic acid and m/z 469.5 for internal standard. The method was validated to be specific, accurate and precise over the concentration ranges of 10–3000 ng/mL with limits of detections of 5 ng/mL for the five triterpene acids. Finally, the method was successfully applied to the pharmacokinetic study of the five structurally similar triterpene acids in rats after oral administration of FEA. Copyright © 2015 John Wiley & Sons, Ltd.     

Simultaneous quantification of atractyloside and carboxyatractyloside in rat plasma by LC‐MS/MS: Application to a pharmacokinetic study after oral administration of Xanthii Fructus extract

Xanthii Fructus is extensively used as an herbal medicine. Ingestion of this herb is associated with severe hepatotoxicity and nephrotoxicity. Atractyloside and carboxyatractyloside are two dominative toxic constituents in Xanthii Fructus. However, their pharmacokinetic study is lacking. In this study, a novel high‐performance liquid chromatography‐tandem mass spectrometry method was developed to simultaneously quantify the rat plasma concentrations of atractyloside and carboxyatractyloside. After protein precipitation, the analytes were chromatographic separated on a ZORBAX Eclipse Plus column (2.1 × 150 mm id, 5 µm) under gradient elute. In the negative electrospray ionization mode, the transitions at m/z 725.3→645.4 for atractyloside, m/z 769.3→689.4 for carboxyatractyloside, and m/z 479.2→121.1 for paeoniflorin (the internal standard) were acquired by multiple reaction monitoring. This analytical method showed good linearity over 1–500 ng/mL for atractyloside and 2–500 ng/mL for carboxyatractyloside with acceptable precision and accuracy. No matrix effect, instability and carryover occurred in the analysis procedure. The extraction recoveries were greater than 85.0%. This method was applied to a preliminary pharmacokinetic study by orally administering Xanthii Fructus extract (9 g/kg) to rats, which was useful to evaluate the role of these two compounds in Xanthii Fructus‐induced toxicity.     

Simultaneous determination of ferulic acid,paeoniflorin, and albiflorin in rat plasma by ultra‐high performance liquid chromatography with tandem mass spectrometry: Application to a pharmacokinetic study of Danggui‐Shaoyao‐San

A rapid, selective, and sensitive ultra‐high performance liquid chromatography‐tandem mass spectrometry method was developed for simultaneous determination of ferulic acid, paeoniflorin, and albiflorin, the major active constituents of Danggui‐Shaoyao‐San, in rat plasma using geniposide as the internal standard. The plasma samples were processed by protein precipitation with acetonitrile, and then separated on a Shim‐Pack XR‐ODS C₁₈ column (75 mm × 3.0 mm, 2.2 μm) using gradient elution program with a mobile phase consisting of 0.1% aqueous formic acid and acetonitrile at a flow rate of 0.4 mL/min. The detection was achieved on a 3200 QTRAP mass spectrometer equipped with electrospray ionization source in negative ionization mode. Quantification was performed using multiple reaction monitoring mode by monitoring the fragmentation of m/z 192.9→134.0 for ferulic acid, m/z 525.0→120.9 for paeoniflorin, m/z 525.2→121.0 for albiflorin, and m/z 433.1→225.1 for the internal standard, respectively. The calibration curve was linear in the range of 5–2500 ng/mL for all the three analytes (r ≥ 0.9972) with the lower limit of quantitation of 5 ng/mL. The intraday and interday precisions were below 12.1% for all the analytes in terms of relative standard deviation, and the accuracy was within ±11.5% in terms of relative error. The extraction recovery, matrix effect and stability were satisfactory in rat plasma. The validated method was successfully applied to a pharmacokinetic study of ferulic acid, paeoniflorin, and albiflorin after oral administration of Danggui‐Shaoyao‐San to rats.